反应详情

3,5-Difluoro-4-(4-trifluoromethyl-pyrazol-1-yl)-phenol (230 mg, 0.871 mmol) was combined with ethyl 4-(1-hydroxybutyl)benzoate (see Intermediate 5) (194 mg, 0.871 mmol) and dissolved in anhydrous tetrahydrofuran (4 mL). Triphenylphosphine (457 mg, 1.74 mmol) was added followed by diazopropyl azodicarboxylate (0.451 mL, 2.18 mmol). This was stirred at room temperature as a yellow solution. At 17 h. the reaction was concentrated. Purification by silica gel flash chromatography (ethyl acetate in heptane) gave impure (+/−)-4-{1-[3,5-difluoro-4-(4-trifluoromethyl-pyrazol-1-yl)-phenoxy]-butyl}-benzoic acid ethyl ester (0.411 g) as a clear oil. 1H NMR (400 MHz, CDCl3, δ): 8.06 (d, J=8.2 Hz, 2H) 7.93 (s, 1H) 7.82 (s, 1H) 7.39 (d, J=8.4 Hz, 2H) 6.54 (d, J=9.4 Hz, 2H) 5.15 (dd, J=7.6, 5.3 Hz, 1H) 4.39 (q, J=7.2 Hz, 2H) 1.96-2.10 (m, 1H) 1.77-1.91 (m, 1H) 1.19-1.61 (m, 5H) 0.98 (t, J=7.3 Hz, 3H); MS (M+1): 469.3.

1. concentrationAt 17 h. the reaction was concentrated
2. customPurification by silica gel flash chromatography (ethyl acetate in heptane)